Differences

This shows you the differences between two versions of the page.

--- principles:low_coupling [2020-10-12 12:35] – old revision restored (2013-02-25 12:08) 159.69.186.191
+++ principles:low_coupling [2020-10-19 20:49] – old revision restored (2020-09-09 20:49) 3.224.127.143
@@ Line 55: / Line 55: @@
   * [[wiki:Examined]]
-  * [[wiki:Accepted]]
+  * [[wiki:Accepted]]: The concept of low coupling is widely known and described in several well-known books for example in Craig Larman's //Applying UML and Patterns//
 /*  * [[wiki:Questioned]]*/
@@ Line 66: / Line 66: @@
 ==== Specializations ====
-  * [[Tell, don't Ask/Information Expert]] (TdA/IE): Adhering to the information expert principle leads to low coupling as there is less need to communicate with other modules to get the necessary information.
   * [[Constantine's Law]]: Constantine's Law is just the combination of the two principles LC and HC.
   * [[Dependency Inversion Principle]] (DIP): LC aims at reducing the dependencies to other modules. One way to do so is to only depend on abstractions. DIP is about this aspect.
@@ Line 74: / Line 73: @@
   * [[Keep It Simple Stupid]] (KISS): Reducing the coupling often involves the use of complicated interaction patterns, indirections, etc.
   * [[High Cohesion]] (HC): A system consisting of one single module has a very low coupling as there are no dependencies on other modules. But such a system also has low cohesion. The other extreme, very many highly cohesive modules, naturally has a higher coupling between the modules. So here a compromise has to be found.
+  * [[Rule of Explicitness]] (RoE): Direct communication typically has the disadvantage of a higher coupling. Indirection reduces coupling but creates implicit/indirect communication paths.
 ==== Complementary Principles ====
+  * [[Tell, don't Ask/Information Expert]] (TdA/IE): IE may help to reduce coupling. Although there are also contrary cases (see [[Tell, don't Ask/Information Expert#caveats]]).
   * [[Model Principle]] (MP): LC aims at reducing the dependencies to other modules. So a module shall depend on only a few others. MP now tells which dependencies are allowed and which aren't.
   * [[Information Hiding/Encapsulation]] (IH/E): Higher forms of couplings (especially content couplings) break encapsulation.
@@ Line 86: / Line 86: @@
 {{page>collections:Principles in "The Pragmatic Programmer"#Box}}
-===== Example =====
+===== Examples =====
@@ Line 101: / Line 101: @@
   * [[wiki>CouplingAndCohesion]]
   * Martin Fowler: //[[http://martinfowler.com/ieeeSoftware/coupling.pdf|Reducing Coupling]]//
+  * Craig Larman: //Applying UML and Patterns – An Introduction to Object-Oriented Analysis and Design and Iterative Development//